Continuous Playback not working after 10.4.4 upgrade until trashing prefs

This is in case somebody upgrades to 10.4.4 and sees this behavior. I upgraded my iMac Pro to Mojave 10.14.1 and FCPX 10.4.4, then upgraded a library I was editing under High Sierra and 10.4.3. After that Continuous Playback in the Event Browser didn't work, even though it was selected in View>Browser>Continuous Playback. I trashed prefs as described in step 11 of this article, then Continuous Playback worked: support.apple.com/en-us/HT203477

Opened an old project as test object (first thing, after having updated to Mojave over HS, was that I saw the beachball very often, this stopped after a clean install). Continuous playback (my default) worked from the start. Found another, quite funny thing: I used to navigate in the timeline with the cursor keys and JKL (skimmer toggled off). But when I now hit down, say, four times, the playhead does not always jump four clips ahead. First off, there is a noticeable lag. Then sometimes it jumps only two clips, sometimes six. Changed the keyboard: doesn't help. Start to use the skimmer instead, which feels more responsive now than before. Weird.